I. Field of the Invention
The present invention relates to an electrical component using a lead frame, and in particularly, to an inductor using a lead frame.
II. Description of the Prior Art
An integrally-formed inductor is made by encapsulating a conductor wire or a coil with a magnetic body instead of winding the conductor wire around an existing magnetic core. Since an integrally-formed inductor has many advantages, such as smaller volume, lower impedance and the endurance for sustain larger current, it has been widely adopted in electronic products that require smaller size, lower power consumption and higher performance.
A known process of making an integrally-formed inductor with low-inductance is illustrated in FIG. 1, including the steps of: (step 1) preparing a coil (e.g., a straight-line-type coil 11 illustrated in FIG. 1); (step 2) adopting a magnetic powder material and performing a thermal-compression process to form an integrally-formed magnetic body 12 encapsulating the straight-line-type coil 11; (step 3) trimming the excessive straight-line-type coil 11 exposed outside of the magnetic body 12; (step 4) performing an electroplating process on two surfaces of the magnetic body 12 to form electrodes 13 which are electrically connected to the straight-line-type coil 11. Because the integrally-formed inductor has a smaller size and the line width of the straight-line-type coil 11 is usually only 60 μm˜70 μm, it is very difficult to fix the straight-line-type coil 11 in the process of forming the integrally-formed inductor; in another aspect, the electrodes 13 formed by the electroplating process can cause instability of the contact resistance, and hence impact the electrical performance of the inductor and reduce the yield rate of the inductor.
Another known process of making an integrally-formed inductor is illustrated in FIG. 2, which includes the steps of; connecting an electrode 14 to the two ends of the straight-line-type coil 11; adopting a magnetic powder material and performing a thermal-compression process to form an integrally-formed magnetic body 12 to encapsulate the straight-line-type coil 11; trimming the electrode 14 according to a design length, bending/modeling the electrode 14 exposed outside the magnetic body 12 so as to adhere the electrode 14 to a lateral surface of the magnetic body 12. Although the structure of the electrode 14 can solve the problem as mentioned in the structure electrode 13 formed by the electroplate process, however, in the structure of the electrode 14, the cross section area of the straight-line-type coil 11 is so small that the joint point 15 between the straight-line-type coil 11 and the electrode 14 will easily rupture from the bending of the electrode 14.